Burden of herpes zoster in adults by age, sex, and underlying conditions in Taiwan: A retrospective cohort study, 2011–2020

The risk of herpes zoster (HZ) and its complications increases with age and is higher in individuals with specific comorbidities. Recent population-level data for HZ disease and health economic burden in Taiwan are limited. We aimed to estimate the incidence of HZ and HZ-related complications, and HZ-related healthcare resource utilization, in the general adult population aged ≥18 years, including subgroup analyses of adults with immunocompromised (IC) conditions, autoimmune diseases (AID) and chronic conditions (CC) in Taiwan. This retrospective, population-based cohort study used claims data from Taiwan's National Health Insurance database between 1 January 2010 and 31 December 2020. The analysis included 1,693,166 adults aged ≥18 years with a primary HZ diagnosis from 2011 to 2020, including 653,414 HZ patients with IC conditions/AID/CC. HZ incidence rates increased over time in the general adult (2011-2020: 7.15-7.82/1,000 person-years [PY], p < .0001) and IC/AID/CC (2011-2019: 9.01-10.28/1,000 PY) populations. Older adults (aged ≥50 years) and patients with IC conditions/AID/CC (versus younger adults aged 18-49 years and the general adult population, respectively) demonstrated higher incidence of HZ and HZ-related complications, and healthcare utilization. Individuals with specific underlying IC conditions/AID/CC (e.g. human immunodeficiency virus infection [24.52/1,000 PY]) had substantially higher HZ incidence rates than others (e.g. stroke [8.39/1,000 PY]). Patients with HZ developing postherpetic neuralgia (versus non-pain complications) had substantially greater outpatient visits and associated costs. Findings demonstrate the considerable disease and health economic burden of HZ in Taiwan, particularly in older adults and the IC/AID/CC population. These results highlight the need for strengthening prevention strategies, with vaccination as a key public health intervention, to reduce HZ incidence and complications.